Need help identifying Microbiology lab UNKNOWN!

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    • #18047

      PRS: Positive for fermentation (acid) + gas
      PRL: Positive for fermentation (acid) + gas
      PRG: Positive for fermentation (acid) + gas
      Citrate: Negative (was a green color)
      MR: Positive (all red)
      VP: Negative (no red color)
      Nitrate: Positive w/o adding zinc (nitrate to nitrite)
      Thioglycollate Broth: Shows Facultative Anaerobic
      SIM: Negative for H2S (no black), Positive for indole and motility
      Nutrient Gel: Negative (stayed gelatin in cold water)
      Urea: Negative (no color change)
      Motility: Positive
      Litmus Milk: Negative for Casin (no curd), positive for acid, neg for Litmus Reduction (turned pink)
      Catalase: Positive (bubbles)
      Oxidase: Negative
      TSI: Positive for Glucose, Lactose and/or sucrose fermentation, negative for gas
      Pheny: Negative (no color change)
      Tryptone Broth: Positive for Indole

      Spirit Blue: Negative
      EMB: Positive for growth and purple sheen (? might have been green at first since one of my plates grew with a green metallic sheen like E.Coli does but might of changed to purple after a couple weeks of being refridgerated but now I forget unfortunately)
      PEA: Negative, no growth
      NA: Positive for growth, no color
      Mannitol Salt: Negative, no growth.

      As for adding Iodine to a starch plate, I stupidly forgot to record the results but I’m pretty sure the entire plate turned black (not sure if thats a positive or negative result)

      Gram Stain showed Gram Positive rods, which is why I’m leaning toward some kind of Bacillus, Corynebacterium or Clostridium. Unfortunately, I forgot to look for spores (and have a hard time finding them anyway) and as some charts suggest online, E. Coli matches most of my tests as well (so could it be a possibility that I might have read my gram stain wrong, as stupid as that sounds?) Most charts show conflicting results on most Bacillus and I’m just getting overwhelmed at this point.

      Any help or suggestions? I first decided on Bacillus Polymyxa but asked my professor if that was a candidate and she said no (yeah, she didn’t give us a list of ALL the possible unknowns – so unfair and frustrating!)

      Answers aren’t needed, but any kind of help you can provide to help me pick a direction would be extremely appreciated!

    • #115745

      Very comprehensive post here. I really loved it. Thanks

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